Recent observations with the Imaging X-ray Polarimetry Explorer (IXPE) of two anomalous X-ray pulsars provided evidence that X-ray emission from magnetar sources is strongly polarized. Here we report on the joint IXPE and XMM-Newton observations of the soft γ-repeater SGR 1806-20. The spectral and timing properties of SGR 1806-20 derived from XMM-Newton data are in broad agreement with previous measurements; however, we found the source at an all-time low persistent flux level. No significant polarization was measured apart from the 4-5 keV energy range, where a probable detection with PD = 31.6% ± 10.5% and PA = − 17 .° 6 − 15 .° 0 + 15 .° 5 was obtained. The resulting polarization signal, together with the upper limits we derive at lower and higher energies (2-4 and 5-8 keV, respectively), is compatible with a picture in which thermal radiation from the condensed star surface is reprocessed by resonant Compton scattering in the magnetosphere, similar to what was proposed for the bright magnetar 4U 0142+61.

IXPE and XMM-Newton Observations of the Soft Gamma Repeater SGR 1806-20

Bonino R.;Massaro F.;
2023-01-01

Abstract

Recent observations with the Imaging X-ray Polarimetry Explorer (IXPE) of two anomalous X-ray pulsars provided evidence that X-ray emission from magnetar sources is strongly polarized. Here we report on the joint IXPE and XMM-Newton observations of the soft γ-repeater SGR 1806-20. The spectral and timing properties of SGR 1806-20 derived from XMM-Newton data are in broad agreement with previous measurements; however, we found the source at an all-time low persistent flux level. No significant polarization was measured apart from the 4-5 keV energy range, where a probable detection with PD = 31.6% ± 10.5% and PA = − 17 .° 6 − 15 .° 0 + 15 .° 5 was obtained. The resulting polarization signal, together with the upper limits we derive at lower and higher energies (2-4 and 5-8 keV, respectively), is compatible with a picture in which thermal radiation from the condensed star surface is reprocessed by resonant Compton scattering in the magnetosphere, similar to what was proposed for the bright magnetar 4U 0142+61.
2023
Inglese
Esperti anonimi
954
1
88
96
9
https://arxiv.org/abs/2308.01238
FRANCIA
GERMANIA
STATI UNITI D'AMERICA
GIAPPONE
4 – prodotto già presente in altro archivio Open Access (arXiv, REPEC…)
262
99
Turolla R.; Taverna R.; Israel G.L.; Muleri F.; Zane S.; Bachetti M.; Heyl J.; Di Marco A.; Gau E.; Krawczynski H.; Ng M.; Possenti A.; Poutanen J.; B...espandi
info:eu-repo/semantics/article
none
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/1999692
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